In recent years, material handling devices have been devised in the form of low-cost planar air pallets employing flexible film plastic material in either sheet or bag form for the transport of material in lieu of conventional wooden pallets. U.S. Pat. No. 3,948,344, entitled "Low Cost Planar Air Pallet Material Handling System," issuing Apr. 6, 1976, is exemplary of such planar air pallets formed of flexible sheet material. Planar air pallets of this type employ at least one flexible material sheet for partially defining a plenum chamber, with that sheet being perforated as by way of small pinholes over a central surface area which faces an underlying fixed, generally planar support surface, such as a building floor. The escape of air under pressure through the perforations which open up directly to the interior of the plenum chamber acts initially to jack the load above that flexible sheet and to create an air bearing of relatively small height between the floor and the perforated flexible sheet. In devices such as those provided within the reference patent, due to cracks within the surface over which the air bearing or air cushion moves as well as projections and irregular contouring of that floor or support surface, it is necessary to provide controlled pillowing of the flexible film defining a portion of the plenum chamber, and to establish by jacking the load to a predetermined height, the ability of the air pallet to ride over such surface projections, while preventing ballooning of the flexible sheet or film portion of the plenum chamber which would result in tilting and thus rolling of the load off the top of the air pallet. Further, where the load is resting upon the air pallet prior to pressurization of the plenum chamber, the load tends to press the perforated flexible sheet into contact with the floor and prevent the entry of air under pressure and escape of the air through the perforations to form an air film of predetermined height to thus create the air bearing for the air pallet.
There is a requirement to provide air dispersion means either interiorly of the plenum chamber or by way of positive members attached to the exterior surface of the flexible sheet or other members defining the plenum chamber such that air entering through an inlet within a wall of the plenum chamber may disperse throughout the plenum chamber and effect jacking of the load and creation of the air bearing. Further, where there are multiple air inlets to the plenum chamber permitting versatility in the point of application of air under pressure, as from compressor, through a supply tube, such as a vacuum cleaner wand (using positive air pressure rather than vacuum to the wand), it is conventional to employ some type of valve member to close off the unused inlet. This is achieved automatically by the utilization of air pressure within the plenum chamber. In the reference patent, this has been achieved by the provision of a flap formed at the air inlet as an extension to one of the thin, flexible sheets defining a wall of the plenum chamber, such as the flexible sheet bearing the perforations and creating the air bearing, with that flap being a bent over a portion of the sheet internally of the inlet, projecting inwardly of the plenum chamber and contacting an overlying or underlying opposed sheet or wall member to seal off and prevent the escape of air through the slit between the sheets defining the air inlet at that point.
Further, the air pallet of the reference patent takes various forms, including in one form a single, flexible sheet which is bonded to the load about the periphery of the sheet and with the load itself forming one wall of the plenum chamber and constituting a relatively rigid backing member. Alternatively, a flexible, plastic film bag, such as a "garbage bag," is employed to form both the upper and lower walls of the plenum chamber and with the lower wall being perforated to define the air bearing and wherein the bag is fixed to the bottom of the load. The air inlet in this case normally comprises the open end of the bag which sealably receives the wand or air supply tube.
In these air pallets, the air dispersion means may comprise a corrugated sheet interposed between the load itself and the single, flexible sheet bearing the perforations in the load bearing area of the air pallet, or the air dispersion means may constitute a corrugated or other irregular surface planar sheet carried internally of the air bag and providing additionally, the generally rigid backing surface for the load.
In the medical field, there is a continuing need to easily, safely and comfortably transport an injured person, hospital patient or the like, such as removing the injured person from the scene of the accident, placement of that person within an ambulance, transportation of the patient within the ambulance to the hospital, transfer of the patient to the operating table and placement of the patient on an hospital bed. Further, there is a very great need for simplified means for moving the patient on the bed to change the bed clothes and to support the patient with maximum comfort and to minimize the possibility of the development of bed sores during long stays in the hospital. Such mechanism must be one in which the material contacting the patient can be readily disposed of and has the capacity to absorb liquid since patients often experience loss of bodily fluids with resultant messing of the bed linen and the like. Further, because of the necessity to prevent transmission of disease, there is the further necessity to provide a low-cost, "throw-away" disposable pad or stretcher cover which can be readily replaced from patient to patient.
The medical supply field has developed rectangular laminated sheet structures known in the art as "chucks" which are comprised of an underlying liquid impervious or non-porous plastic film bearing a soft porous sheet material layer and covered by a gauze sheet, which laminated structure is placed directly beneath a patient, either on a hospital bed or under similar circumstances. This allows the chuck to be readily disposed of subsequent to its use as when soiled or when the equipment bearing the chuck receives a new patient.
It is, therefore, a primary object of the present invention to provide an improved patient mover which facilitates the movement of a patient or accident victim and permits the patient to be physically moved in a relatively frictionless manner.
It is a further object of the present invention to provide an improved patient mover which is preferably formed of flexible film material which provides for an air bearing facilitating that frictionless movement of the patient and which preferably incorporates an absorbent material chuck as a material element thereof to provide for the comfort and needs of the patient during such handling.
It is a further object of the present invention to provide an improved low-cost disposable air-bearing patient mover which has application to emergency use at the scene of an accident and which will permit the accident victim to be transported directly from the scene of the accident to the hospital and facilitate patient transport throughout the hospital with minimum disturbance to the patient during such movement.